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BACKGROUND: Tungsten molybdenum ores are strategic mineral resources. China is a large producer and consumer of tungsten and molybdenum ore. Accurate and efficient analysis of tungsten and molybdenum and its associated beneficial and harmful elements is of great significance for the evaluation and comprehensive utilization of tungsten and molybdenum ore deposits. Acid dissolution and alkali fusion are the general digestion methods in tungsten molybdenum ore analysis. However, the acid solution method cannot be used to overcome the hydrolysis problem when treating samples with high content of tungsten and molybdenum, whereas the alkali fusion method such as sodium peroxide and sodium hydroxide usually introduces a large content of alkali metals, so the determination of potassium and sodium cannot be finished. OBJECTIVES: To find an efficient method for the determination of tungsten, molybdenum and 11 other elements in tungsten molybdenum ore. METHODS: Lithium metaborate melting-tartaric acid ultrasonic leaching and inductively coupled plasma-optical emission spectrometry (ICP-OES) was used for the simultaneous determination of tungsten, molybdenum, copper, lead, zinc, aluminum, iron, calcium, magnesium, titanium, manganese, potassium and sodium in tungsten-molybdenum ore. The sample was completely digested by lithium metaborate fusion. No other elements were introduced except for B and Li. Tartaric acid was used to inhibit the hydrolysis of tungsten and molybdenum. Ultrasonic leaching speeds up the dissolution of the frit. RESULTS: The experiment optimized the analysis spectrum and observation method of each element, compared the amount of flux and instrument conditions to obtain the best conditions, and used the matrix matching method to draw a standard curve to eliminate the influence of the matrix effect. The linear correlation coefficient of the standard curve of each element was greater than 0.9990, the detection limit of the method was 1.34-46.2μg/g, the relative error of measured results was 0.14%-8.7%, the relative standard deviation (RSD, n=10) of the measured results was 1.4%-7.6%. CONCLUSIONS: This method can accurately and efficiently complete the simultaneous determination of multiple elements in tungsten and molybdenum ore samples. [ABSTRACT FROM AUTHOR]

BACKGROUND: Sepiolite is a widely used fibrous magnesium-rich silicate clay mineral. Sepiolite is mainly composed of silicon and magnesium, with minor aluminum, potassium, sodium and other impurities. Determination of the major element of sepiolite usually adopts the classical chemical analytical method. After the alkali melting treatment, the sample is determined by volumetric method, photometry and atomic absorption spectrometry, which is inefficient and time-consuming. Moreover, potassium and sodium cannot be simultaneously determined.OBJECTIVES: To find an efficient method for the determination of seven major elements in sepiolite.METHODS: The samples were digested by hydrofluoric acid, nitric acid, and perchloric acid. Contents of major elements such as Al2O3 were determined by inductively coupled plasma-optical emission spectrometry（ICP-OES）. The dosage of hydrofluoric acid was optimized. The analytical spectral lines were Al 396.153 nm, Ti 334.940 nm, K 766.490 nm, Na 589.592 nm, Ca 422.673 nm, Mg 285.213 nm and Fe 238.204 nm, and elements were determined by axial observation. The content of magnesium in sepiolite was high, and there was a certain matrix effect during ICP-OES analysis. A series of high magnesium mixed standard solutions were prepared to match the matrix.RESULTS: The linear correlation coefficient of the standard curve of each element was greater than 0.9990, the detection limits of the method were 0.53-3.25μg/g, the relative standard deviations（RSD, n=10） of the measured results were 0.66%-5.65%, and the recoveries of each element were 95.3%-108.5%.CONCLUSIONS: Acid dissolution is easy to operate compared with the alkali fusion method. The results are consistent with those obtained by classical chemical analytical methods and thus meet the analytical requirements of sepiolite samples. [ABSTRACT FROM AUTHOR]

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Copyright of Rock & Mineral Analysis is the property of Editorial Board of Rock & Mineral Analysis and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)